Arch Linux

xmathe

Member

Registered: 2014-11-26

Posts: 6

[Solved]Boot halts, root device not found

Hi all, out there,

I am using Arch and Mint 17 KDE. Due to well known Xorg vs AMD/Intel issue the Mint had to be reinstalled (or at least it seemed to be easier to reinstall it). Unfortunately the grub had originally been set by Mint and it happened the same way during the Mint reinstallation.
Arch is recognized by grub but at kernel load the boot halts and "Error: device 'UUID=.... not found," "hwdb.bin not found" messages appear.
Made some mining in fora in quite a panic and found some good-looking suggestions in pacman section of Arch Wiki. I tried to follow the instructions there, even reinstalling the mkinitcpio, systemd and linux was "successful" but at next boot i got the same error messages again.

Can anyone give some hints -- appreciated in advance -- how could I proceed?
The biggest problem for me is that Arch is my real work-horse (in the strict sense of the word), Mint is mostly for playing around.

Thanks

Attila

Last edited by xmathe (2014-11-30 20:12:43)

ratcheer

Member

Registered: 2011-10-09

Posts: 924

Re: [Solved]Boot halts, root device not found

Run blkid as root and make sure the UUID hasn't changed.

Tim

xmathe

Member

Registered: 2014-11-26

Posts: 6

Re: [Solved]Boot halts, root device not found

Thanks Tim for prompt reply. I have already done it and it does not seem to be altered. The actual result of blkid shows the specific (in my case sda4) uuid is identical with what the kernel is looking for at boot up but does not find.

A.

Spider.007

Member

Registered: 2004-06-20

Posts: 1,176

Re: [Solved]Boot halts, root device not found

When you end up in the emergency shell, is the uuid listed in /dev/disk/by-uuid/ ? If you manually mount your disk to /new_root there; your boot should continue and you might be able to fix your grub.cfg

Last edited by Spider.007 (2014-11-26 19:17:10)

TheSaint

Member

From: my computer

Registered: 2007-08-19

Posts: 1,536

Re: [Solved]Boot halts, root device not found

@ Spider.007, maybe I could read thousand of pages, but this is the best knowledge I found. Thank you.

Last edited by TheSaint (2014-11-26 19:39:13)

---

do it good first, it will be faster than do it twice the saint

xmathe

Member

Registered: 2014-11-26

Posts: 6

Re: [Solved]Boot halts, root device not found

When you end up in the emergency shell, is the uuid listed in /dev/disk/by-uuid/ ? If you manually mount your disk to /new_root there; your boot should continue and you might be able to fix your grub.cfg

Thanks, @Spider.007 and i apologize for reacting with such a delay (am in Africa now and i was working in the outbacks where i can be happy with sole cell coverage, no dreams about internet access).
The case is that grub was set by the other linux distro, not by Arch. And by now I got totally confused with these uuids, what is looking for what and where... 

xmathe

Member

Registered: 2014-11-26

Posts: 6

Re: [Solved]Boot halts, root device not found

It is now sure that the disk UUIDs somehow don't make up consistent cross compliance.
I made a full boot info file:

http://paste2.org/LmmJdGtH

The active grub (on sda2 -- LMint17) sets the arch (sda4) UUID properly (line# 336, 338), i.e. identical to the UUID in sda4/etc/fstab.
However the sda4/boot/grub/grub.cfg shows something different (line# 474, 476 and below under the advanced options section too.) 

That's what I see now.

I guess....
No, I don't guess anything.

Thanks for any hints.

A.

Last edited by xmathe (2014-11-30 09:35:26)

Spider.007

Member

Registered: 2004-06-20

Posts: 1,176

Re: [Solved]Boot halts, root device not found

Grub doesn't set the uuid; that is a fixed property of the filesystem. However; I think you're right, there are multiple /boot directories which is obviously going to cause issues like this. For a quickfix; mount sda4 and copy the grub.cfg from sda2 to it.

For a more permanent solution you should uninstall grub on 1 install (probably easier to do with Arch) and then make sure the Mint-grub sees your Arch install so it lets you boot to it. Eventually you could remove the bootloader from both partitions (grub should be installed to sda, not sdaX).

xmathe

Member

Registered: 2014-11-26

Posts: 6

Re: [Solved]Boot halts, root device not found

For a more permanent solution you should uninstall grub on 1 install (probably easier to do with Arch) and then make sure the Mint-grub sees your Arch install so it lets you boot to it. Eventually you could remove the bootloader from both partitions (grub should be installed to sda, not sdaX).

And that was it! You just rock, Spider.
I purged the grub out from arch, reinstalled mkinitcpio, systemd and linux. Reinstalled existing grub in mint... and tadaaa now i am typing from the again bootable arch.

Thanks a lot for you and everyone who tried to (and really did) help me!!!

Spider.007

Member

Registered: 2004-06-20

Posts: 1,176

Re: [Solved]Boot halts, root device not found

Great, nice to hear you fixed it; could you mark this thread as fixed by editing the first post as well?

xmathe

Member

Registered: 2014-11-26

Posts: 6

Re: [Solved]Boot halts, root device not found

Great, nice to hear you fixed it; could you mark this thread as fixed by editing the first post as well?

Done.

Thanks again for the extra hint {i have been searching at least for half an hour how to mark the thread as solved...} :-D